GP44A-01:
Ionosphere-Magnetosphere Coupling from Dynamics Explorer to Swarm and Beyond
Thursday, 18 December 2014: 4:00 PM
Thomas Earle Moore1, James H Clemmons2, Glyn Collinson1, Daniel J Gershman1, George V Khazanov1, Lynn M Kistler3, David J Knudsen4, Robert F Pfaff Jr1, Craig J Pollock1 and Douglas E. Rowland1, (1)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (2)Aerospace Corporation Pasadena, Pasadena, CA, United States, (3)University of New Hampshire Main Campus, Durham, NH, United States, (4)University of Calgary, Calgary, AB, Canada
Abstract:
Ionospheric plasmas have thermal speeds much smaller than orbital (escape) velocities, so they appear to orbiting spacecraft as a relatively narrow beam from the ram direction. But one of the very interesting things about ionospheric plasmas is that they are heated strongly in the auroral zones, and accelerated such that their thermal or directed speeds exceed orbital or escape velocity. Then they do just that: orbit or escape the Earth into the magnetosphere and beyond at velocities spread over a large range of angles and magnitudes. This has created a dichotomy between the observation of cold, rammed plasmas in the ionosphere proper and the observation of hot plasmas with a large range of velocities in both direction and magnitude, well above the ionosphere proper. The former are usually observed from attitude-stabilized, ram-pointed spacecraft, while the latter are usually observed from spinning spacecraft. We review measurements that illuminate the way forward, particularly from the Swarm mission, and propose a new sciencecraft configuration that overcomes the divergent requirements to facilitate direct observations of processes that heat and accelerate ionospheric plasmas across this transition from gravitationally bound to unbound and escaping into space.
